Conventional articulated overhead doors operate using devices such as counterweights, springs, lifting straps, and/or hydraulic systems. Disadvantageously, such systems are bulky and not inherently failsafe should a major component fail, such as a chain, cable, or hydraulic line. The key to operation and articulation of these types of doors is the action and forces required to start the door to fold, or articulate, as it starts to lift. Articulation of the door requires that a force be applied perpendicular to the door face, while lifting the door to start the section hinging or folding action. This action can be referred to as “Breaking the elbow.” Conventional designs utilize extended arm profiles that extend into the space in order to start this action which distracts from the aesthetic of the door and is prone to damage since they extend into the interior space. This also adds to the required clear space to be maintained in order for the door to operate without interference.
Many articulated door designs utilize heavy counterweights in order to easily operate the door. These counterweights lift up and down with the operation of the door and are most often suspended from cables and guided through the vertical structure of the door frame. The mass or weight of the counter weights are dependent on the weight of the door frame structure and all of the cladding that is mounted onto the operable door frame. Doors systems are typically shipped without cladding and pre balanced from the factory based on the frame weight only. Adding cladding and other components to the door necessitates the recalibration of the mass of the counterweights in order for the door to operate properly. On doors such as this, the counterweights can easily weigh in the hundreds of pounds. With other designs, these counterbalance forces are applied using large coil spring systems instead of counterweights.